Annealing apparatus



ec. 22, 1931. H. VON FORSTER ET AL 1,338,915

ANNEALING APPARATUS Filed June 15. 1927 5 Sheets-Sheet l Dec. 22, 1931. VON F'QRSTER ET AL 1,838,015

ANNEALING APPARATUS Filed June 15. 1927 5 Sheets-sheet 2 9&1. 1931? H. VON FORSTER ET AL 1,838,015

ANNEALING APPARATUS Filed June 13. 1927 5 Sheets-Sheet 3 Fig. 3.

[in wen tars:

1931- H. VON FoRsTz ET AL 1,838,015

ANNEALING' APPARATUS Filed June 13. 1927 5 Sheets-Sheet 4 Fig. 5.

@360 H. VON FORSTER ET AL ANNEALING APPARATUS Filed June 13 1927 Patented Dec. 22, 1931 UNITED STATES PATENT OFFICE EEBMANN VON FOBSTER AND EMIL LAY, O F HEDDEBNHEIM, NEAR FBANKI'OBT-ON- THE MAIN, GERMANY, ASSIGNORS, BY MESNE ASSIGNMENTS, TO AKTIENGESELL- SCHAFT BROWN BOVEBI & CIR, OF BADEN, SWITZERLAND, A JOINT-STOCK COH- PANY ANNEALING- APPARATUS Application filed June 18, 1927, Serial No. 198,613, and in Germany December '1, 1926.

This invention relates to a device for cleaning and polishing metal pieces by heating them.

For cleaning and polishing pieces of metal such as wires, plates, sheets or the like by heating there have already been proposed devices consisting of a heating chamber, in which the articles are kept for a certain length of time at a certain temperature, and

a cooling chamber, in which the treated articles are cooled. The heating chamber and cooling chamber are usually filled with inert gases protecting the surface of the articles from tempering or the like. The cooling chamber is as a rule permanently attached to or integral with the heating chamber. But it has already been proposed to make the cooling chamber movable with respect to the heating chamber. The articles to be treated are carried by a suitable heating frame in the cooling chamber which is placed above the heating chamber and from which the frame is lowered down into the heating chamber. A plate arranged on the heating frame above the articles served as closure for the furnace from the cooling chamber remaining during the heating process above the heating chamber. This known device has however many disadvantages. In the first place the cooling chamber above the heating chamber is heated more or less durthe heating process thereby increasing time necessary for cooling. On account the high temperature and their resultant l specific weight, the protective gases ours rapidly leave the furnace, when sc /a mg the cooling chamber from the heating. chamber, thus making greater amounts-ref protective gases or vapors necessary. Themen attending the device are also troubled by'lthe heat radiated from the fur nace and thelatter is strongly cooled down.

Of still more importance is the disadvantage,.,:'

that the location "of the cooling chamber above the heating chamber makes it difficult to secure access to the latter during the heating operation, and that observation of the articles being heated is either impossible or unsatisfactory.

All these disadvantages are avoided according to the invention by connecting the cooling chamber from below to the heating furnace and by making it removable from the furnace during the heating process. The latter may therefore be regulated with more care and the o eration of the device is materially simpli ed.

Further important features of the invention are the special constructions of the device for carrying the material from the cooling chamber into the furnace and back again, of the closure between cooling and heating chamber and of the cooling chamber.

The annexed drawings show several preferred forms of carrying the invention into practice by way of example. Figures 1, 2, 3 and 5 show several complete devices in section and Figures 4 and 6 cooling devices especially adapted for using them in combination with the heatingfurnace also in section.

In Fig. 1 the furnace 1 is provided with a stuffing box 2 through. which there passes a sliding rod 3 carrying the articles to be heated. In the upper part of the furnace 1 is arranged the entrance openin 4 for the protective gases. The closure of t e furnace I 1 takes the form of a slide 5 having on the lower side a hollow for the reception of the cover 6 for the cooling vessel 7. The slide 5 is arranged in a box 8 and may be operated by a rod 9 which extends outside the box 8 and is guided for sliding movement by a substantially gas tight stufiing box. The cooling vessel 7 'is arranged transportably upon a carriage 10. Below the furnace 1 is arranged a device 11 for raising and lowering the carriage 10 with the cooling vessel 7. The latter may be connected to a conduit 12 for the protective gas and has an opening 13 for The device works as follows: The furnace 1 may be charged with articles to be heated from the cooling vessel 7 or in any other way. As the feeding opening is at the bottom of the furnace there will be no material loss of the protective gases in the heated furnace chamber 1 when the chamber is opened for short periods. Considerable amounts of gas cannot escape and explosions are not to be feared, for the protective gas is lighter than the surrounding air, thus preventing the mixture of great amounts of protective gas with the air. v

During the heating process protective gas is introduced through the opening 4 into the furnace 1 in such amounts that at the leaks of the bottom closure or at a special opening a small flame is burning This is a guaranty therefore, that the furnace is always filled with protective gas.

hen the heating process is finished the cooling vessel 7 with cover 6' is pressed by the raising device 11 against the furnace 1 in such a manner that the cover 6 enters the hollow of the slide 5. The cover 6 is drawn. back together with the slide 5 and the gas will then enter the cooling vessel 7 until the small flame 1 1- can be produced at the openin 13. As soon as the cooling vessel 7 is filled with gas the heated material is lowered into the cooling vessel 7 by lowering the rod 3. This rod 3 is then disconnected by operation of the automatic P coupling 18, and raised, again, The gas tube 12 is connected to the cooling vessel 7 and the slide 5 is closed, thereby closing thevessel 7 by the cover 6. The interior of cooling vessel 7 is then not only closed against the furnace 1 but also protected against the atmospheric air when the vessel 7 is lowered and carried away with the carriage 10. The covert; may then also be fastened by the clamps to obtain a better tightening. The burning of the control flame 14 is an indication therefore, that the heated material is always in an atmosphere of protective gas. It is obvious that the cooling vessel 7 may already be filled with protective gas before connecting it to the furnace 1.

When the cooling vessel 7 is removed the furnace 1 may be charged with new material to be heated. By using a suitable amount of cooling vessels 7 the heating and the cooling process may be carried through without dis- 65 turbing each other.

the furnace 1 is movable and the cooling chamber stationary. For corresponding parts are used the same numerals as in Figure 1. The same is the case in the devices shown in Figures 3, 4, 5 and 6.

In operation the movable furnace 1 is placed over the hole 21 and the material to be treated is raised from below into the furnace 1 by the raising table 22, which is raised so high that it touches the projections 23 of the slide box. When the heating process is finished the raising table 22 is lowered into the hole 21 filled with protective gas and the furnace slide 5 carrying the cover 6 for the hole 21 is closed. The furnace 1 may then be raised by the raising and transporting device 24 and moved to the next cavit for cooling. A flame 14 for controlling the lling of protective gas in the cooling chamber may also be provided.

The device as shown in Figure 3 differs from that in Figure 1 only by a special and more simple construction of the closures for furnace and the cooling chamber. The closures consist of plates 25 and 26 on the frame 17 carrying the material to be hea (1. Slide 5 and cover 6 as used in Figurj 1 and 2 are then avoided. When the ma erial to be heated upon the frame, 17 is raised into the furnace 1 by the rod 3, the plate 25 contacts with the lower surface of an annular intermediate member 27 which is thereby pressed against the walls of the furnace around the charging opening, closing it tightly.

When the heating process is finished, the cooling vessel 7 is pressed against the intermediate member 27 by the raising device 11. The upper rim-0f the cooling vessel 7 is provided with a flange 28 constructed in such a manner that it engages with the outer rim of the intermediate member 27, when the cooling vessel 7 is pressed against the furnace 1.

When the'heated material is lowered into the cooling vessel 7 the cover plate 26 provided wth a conical border engages with a corresponding conical part 27 thereby clos-- ing the opening of the cooling vessel 7. The rod 3 is then disconnected from the frame 17 by means of the coupling 18. It is not necessary to provide for a special fastening device such as clamps for the cover 26, because the weight of the material hanging on the cover 26 provides for a closure of sufficient tightness. The cooling vessel 7 is filled with protective gas preferably before charging it with heated material and connected to the protective gas tube-12 during the transportation and the cooling process.

If cheap and impure protective gases such as illuminating gas, generator gas or the like are used for heating metals such as hand iron or wires, care must be taken that the protective gases do not come in direct contact with the material to be heated, because impurities such as tarr constituents and the like would be deposite upon the metal, spoiling the quality of the finished product. In these cases the material to be treated is arranged during the heating in a special vessel, protecting it against direct contact with the impure protective gases introduced into the furnace. The protecting gas enters into this special vessel by passing layers of finely distributed metal thereby purifying it. The presence of air in this special vessel in the beinning of the operation has proved to be innoxious, as its oxygen is combined with the entering gas and the fat and oil films adhering to the metal in a short time.

he protective gas entering the furnace is thus carefully purified before entering the special vessel, as it passes only very slowly the layer of the finely distributed metal, thereby coming into intimate contact with this metal.

As the special vessel is continuously surrounded by protective gas during the heating and the cooling step, no oxidation of this vessel occurs. The special vessel may therefore have thin walls, improving the heat conduction, is cheap, and lasts a long time.

A device of the kind, in -.which impure protective gas may be used, is shown in Figure 5. The material to be heated, for example coils of iron 16, is arranged in the interior of an iron pct 32 with thin walls carried by the plate 26, similarly as in Figure 3. The pot 32 may be reinforced by ribs. Between the plate 26 and a perforated cover 34 are placed cast iron chips or similar purifying agents 33. The protective gas, for example illuminating gas, introducted by the tube 4, enters the upper part of the furnace 1 and leaves the latter in the lower part,

where the flame 19 is burning. During the heating process the protective gas passes the purifying material 33, before it reaches the material 16 to be heated. Furnace and cooling vessel are constructed as described above. There is arranged only a sliding closure for the furnace besides the plate 26, covering the cooling vessel 7 when the heated material has been lowered into said vessel 7. Before the heating pot 32 has been transferred into the cooling vessel 7, theair is displaced from the vessel by filling it with gas through the tube 12. The cooling vessel also obtains a safety and control flame 14. The pot 32 is kept filled with protecting gas, until the heated material is completely cooled.

The heat necessary for the heating process may be produced in the interior of the furnace itself, for example by an electric resist ance, thus obtaining an especially good trans- .fer of heat onto the material to be heated.

filled with protective gas.

As shown in Figure 3 and more particularly in Figure 4 the cooling vessel 7 may be provided with a special gas-tight closure, in order to prevent losses of protective gas. This closure consists of a bell 30 engaging with an oil filled container 31. This device is especially adapted, when using expensive protective gases such as hydrogen.

When filling the cooling vessel with a combustible protective gas the air in the vessel may be removed by using it for the combustion of a part of the protective gas. The cooling vessel is then preheated, which is of advantage in certain cases. If however this preheating is to be avoided the air is removed from the cooling vessel by introducing steam or other gaseous substances not reacting with the protective gas, before filling the vessel with protective gas.

When the heating of the material for example of copper, is done in an atmosphere of steam, the cooling may also be effected by steam, naturally only until such a temperature is reached at'which the steam is not yet condensed and other rotective gases, such as illuminating gas, by rogen or the like do not have a bad influence upon the heated material. As soon as this temperature is reached, the steam is replaced by a protective gas, which, for example, is introduced into the cooling vessel in such a manner that it drives the steam out in order to prevent the deposition of Water uponthe heated material. Thecooling is then finished in the atmosphere of protective gas. In many casesit is of advantage to go down to a temperature near the condensation temperature of the steam.

It has further been found to be of advantage to hasten the cooling process as much as possible in order to obtain a better material and to cheapen the process by saving cooling vessels. For this purpose the cooling vessel is provided with a jacket passed by cooling water during the whole or a part of the cooling process. For the great drop of temperature then taking place'in the cooling vcssel the contraction of the protective gas is great and care has to be taken therefore, that no air enters the cooling vessel. The cooling vessel is therefore connected to a gasometer filled with protective gas, so that any-amount of gas may be sucked into the cooling vessel at any time. I-

Figure 6 shows such a cooling device b way of example. The cooling vessel 7 with water jacket 37, cover 6 and bell 30 in an oil or water filled ring container 31, is provided with a water tube 38 and steam exit 39, and connected to the gasometer 40. 41, 42 and 43 are stop valves 1n the tubes 44, 45 and 46. 47 is a valve in the bell 30.

After the heated material has been brought into the cooling vessel, the cover 6 is placed more or less automatically, when closing the slide between the heating and the cooling chamber. After the cooling chamber has been transported away from the heating chamber the bell 30 is placed to obtain a better closure against the atmospheric air. Before and during the transport of the heated material into the cooling vessel 7 the latter is filled with steam entering by the tube 46. The air in the room between the cover 6 and the bell 30 is displaced by the steam lzaking through the cover 6, when the valve 47 is opened. The gasometer 40 isin the meantime filled with protective as by the tube 45 coming from a source 0% gas. After the air in the bell 30 has been removed by the steam, the valve 41 is opened and protective gas introduced. into the cooling vessel. At the same time cooling water enters the jacket 37 by opening 38. In order that the steam produced in the beginning may leave the jacket 37 as quickly as possible the steam exit tube is made as wide as possible. By the strong cooling then taking place the steam in the interior of the cooling vessel 7 is condensed but deposited only on the water cooled walls of the cooling vessel 7 and not touching the heated material. At the same time great amounts of gas are drawn from the gasometer 40 into the cooling vessel 7. W'hen the cooling is finished the valve 41 is closed and the cooled and heated material may be taken out from the cooling vessel 7.

The cross section of the furnace is not limited to be circular as shown in the drawings but may have any desired shape.

The invention has proved to be of great advantage for the heating of wires, plates, sheets or the like by electric heating, preferably using electric resistances in the in terior of the furnace for the production of the heat. As the furnace is filled with inert gases during the operation high-melting, oxidizing metals such as iron may be used for the resistances and it is possible to employ high temperatures.

' The expense of the constructiim of the furnace is therefore decreased. On the other hand energy for heating purposes is saved as heating chamber and coolinmchamber are independent of each other and a continuous operation is even possible with small units of the furnace. The use of electrical energy is thus first made economical by working in. at cordance with the invention.

The invention however also presents great advantages when heating by other means. These advantages are principally the simple and clear operation of the device and the great economy obtained with it.

\Ve claim:

1. A device for heating metal pieces in an 5 atmosphere of protective gases comprising a vertically arranged heatin chamber, a cooling chamber arranged be ow said heating chamber, means to provide for a relative movement between said heating and said cooling chamber in all phases of the operation and means to provide for a gas-tight connection between said chambers.

2. A device for heating metal pieces in an atmosphere of protective gases comprising a vertically arranged heating chamber, means for supporting the material to be heated in said heating chamber, a cooling chamber arranged below said heating chamber, means to provide for a relative movement between said heating and said cooling chamber in all phases of the operation and means to provide for a gas-tight connection between said chambers.

3. A device for heating metal pieces in an atmosphere of protective gases comprising 35 a vertically arranged heating chamber, a stuffing box in the top part of said heating chamber, a rod slidable in said stufling box, 7 means to fasten the material to be heated on said rod, a cooling chamber arranged below said heating chamber, means to provide for a relative movement between said heating and said cooling chamber in all bases of the operation and means to provide for a gas-tight connection between said chambers.

4. A device for heating metal pieces in an atmosphere of protective gases comprising a vertically arranged heating chamber, a stuffing box in the top part of said heating chamber, a sliding rod in said stufiing box, a frame attachable to said rod for carrying the material to be heated, means carried by the lower end of said frame and serving as closure for the charge and discharge opening of said heatim chamber during the heating process, a cooling chamber arranged below said heating chamber, means to provide for a relative movement between said heating and said coolin chamber in all phases of the operation and means to provide for a 11 gas-tight connection between said chambers.

5. A device for heating metal pieces in an atmosphere of protective gases comprising a vertically arranged heating chamber a cooling chamber arranged below and in gas-tight connection with said heating chamber, a stufting box in the top part of said heating chamber, a sliding rod in said stufiing box, a frame attached to said rod for carrying the material to be heated, means to provide for a closure of said heating chamber during the heating )rocess carried by said frame, means to provide for a closure of said cooling chamher during the cooling process carried by said frame, means to disconnect said frame from said rod and means to provide for a relative movement of said chambers during all phases of o ration.

6. A device or heating metal pieces in an atmosphere of protective gases comprising a gas tight joint between said chambers,

essors vertically arranged heating chamber, a cooling chamber arranged below said heating chamber, means to provide for a. gas-tight connection between said chambers, a stalling box in the top part of said heating chamber, a sliding rod in said stalling box, a frame for carrying the material to be heated attached to said rod, a plate for closing heating chamber during the heating process carried by said frame, a. plate for closing the cooling chamber during the cooling process carried by said frame, means to disconnect said frame from said rod and means to provide for a. relative movement between said chambers in all phases of operation.

7. Apparatus for heating metal articles in an atmosphere of protective gases, comprising a vertically arranged heating chamber having an open lower end, a substantially gas tight closure for the open lower end of said chamber, a cooling chamber having an open upper end, the adjacent ends of said chambers being shaped to cooperate in forming a and means in one of said chambers and operable from the exterior thereof for transferring articles from one chamber to another.

8. Apparatus for heating metal articles in an atmosphere of protective gases, com- Jrising a vertically arranged heating chamer having an open lower end, a substantially gas tight closure for the open lower end of said chamber, acooling chamber having an a open upper end, conveyor mechanism for movably supporting one of said chambers and adapted to move the same to bring the open ends of said chambers into vertical aline-. ment, the adjacent ends of said chambers be ing shaped to cooperate in forming a gas tight joint between said chambers, and means in one of said chambers and operable from the exterior thereof for transferring articles from one chamber to another.

9. A device for heating metal pieces in an atmosphere of protective gases comprising a vertically arranged heating chamber, stufiing box in the top part of said heating chamber. a rod slidable in said stalling box, means to fasten the material to be heated on said rod. a coolin chamber arranged below said heating chamber, means to provide for relative movement between said heating and said cooling chamber in all phases of the operation and means to provide for a gas-tight connection between said. chamber comprising a ring carried in the upper edge of said cooling chamber, and projecting above the upper edge of saidcooling chamber.

10. A device for heating metal pieces in an atmosphere of protective gases comprising a verticallyarranged heating chamber, a. cooling chamber arranged below said heating chamber, a stufling box in the top part of said heating chamber, a sliding rod in said stufiingbox, a frame for carrying the material to be heated attached to said rod, a plate for closing said heating chamber during the heating process carried by said frame, a plate for closing the cooling chamber during the cooling process carried by said frame, means to disconnect said frame from said rod, means to provide for a relative movement between said chambers in all phases of operation, and means to provide for a gas tight connection between said chambers comprising a ring carried in the upper edge of said cooling chamber and projecting above thenpper edge of said cooling chamber, said ring having an internal diameter less than the external diameter of the aforesaid closing plates.

11. A. device for heating metal pieces in an atmosphere of protective gases comprising a vertically arranged heating chamber, a cooling chamber below said heating cham ber, means to provide for a relative movement between said heating and said cooling chamber and means to provide for a gastight connection between said heating and said cooling chamber, said cooling chamber being provided near its upper edge with an external circumferential channel adapted to provide a. gas-tight liquid seal in coopera-' "tion with a bell-shaped cover during the cooling operation.

12. a device. for heating metal pieces in an atmosphere of protective gases comprising a vertically arranged heating chamber, a cooling chamber below said heating chamber, means to provide for a relative movement between said heating and said cooling chamber, means for supplying protective gases to. said chambers, an means to provide for a gas-tight connection between said heating and said cooling chamber.

13. In an annealing apparatus an inverted heating chamber open at the bottom and supported in an elevated position, a cooling chamber located below said heating chamber for holding the metal before and after annealing, means to provide for relative lateral movement of said chambers to bring the same into vertical alignment, and means for elevating and lowering the metal to be annealed from said cooling chamber into and out of said heating chamber While excluding air from access to said metal.

141-. in an annealing apparatus, an inverted annealing furnace open at the bottom,

magazine, a receiver in said magazine for the metal to be annealed, means to exclude air from the top of said magazine, and,

fore and after annealing, means to provide for a relative movement'of the cooling chambers and said heating chamber to bring the cooling chambers successively beneath and in 5 vertical alignment with said heating chamber, means to elevate the metal from the said aligned cooling chamber into said heating chamber, and means te revent the access of air to the interior of sai chambers.

10 In testimony whereof we affix our signatures.

,HERMANN v. FORSTER. DR. EMIL LAY. V 

